问题
I'm trying to modify this thermal system of a house to make it for an AC instead of a heater. The page says that if I want to modify it I need to add the cold air input part and edit the thermostat. I managed to fix the thermostat and now I can get the status as 1 when the AC is on (temperature drops) and 0 when it's off (temperature rises).
How do I flip the heat transfer equations to get the cold air gain instead of the heat gain. They are using some equations in the link, is it okay to use them as they are and flip the (t_room-t_heater) subtraction or should I use a totally different set of equations.
This is the output when it runs as a heater after changing the thermostat model (I'm interested in the temperature (yellow) and the status(orange))
This is the internal structure of the heater submodel
Now, I changed the subtraction to become troom-theater to get the cold air gain, the answer is as the following:
The blue sine wave is just the outdoor temperature variations. Thanks
回答1:
I made some changes in the sldemo_househeat_data.m file that sets up all the initial points. I changed the follwing values:
% The air exiting the heater has a constant temperature which is a heater
% property. THeater = 50 deg C
THeater = 15;
% TinIC = initial indoor temperature = 20 deg C
TinIC = 26;
I also changed the set point for the AC's temprature as shown in the figure bellow:
Also, my thermostat model was flipped by flipping the sign of the temperature comparison with the set point at the beginning of the diagram. I kept the status (0,1) the same in the relay block, I only flipped them in the heater model as shown in the figure
This way, any 1 set by the thermostat is flipped into a 0 by subtracting it from 1. The same applies to any 0 set by the thermostat.
Inside the house submodel, I flipped the subtraction in the temprature difference equation as the following (tout-tin instead of tin-tout)
Finally, the response of my AC is shown as the following.
I hope this helps ad thanks
来源：https://stackoverflow.com/questions/50352214/simulink-home-thermal-system-as-an-ac